Actually I watch a LOT of movies. A couple a day usually. I pay close attention to things like editing, structure, etc because as an aspiring filmmaker these are the things which interest me. It is possible to interpret the ending as Bruce's death. I'm not necessarily saying that's correct, but that Nolan leaves enough thread to pull on with regards to that interpretation. The other interpretation is equally possible.
Except it's not possible. If Bruce died, that would mean that some scenes are in the movie for absolutly no reason whatsoever. And as Nolan said, he needs 3 reasons to keep a scene in, otherwise he cuts it.
Look at the ending of Inception- the music, the lighting, etc. Compare it to the ending of rises-
http://www.youtube.com/watch?v=YMk_pJPyvSM
As the filmmakers on Nolan fans pointed, there is nothing to suggest Alfred is seeing things. The music especially kicks up right when Alfred realizes Bruce is alive.
Bruce would never kill himself. It would completely defy the nature of his character. He won't be selfish like that and do something that would destroy Alfred. This entire series is about him moving on from pain and getting a life. Him dying would defeat the purpose.
Not to mention that the ending is from dark knight returns (a favorite of the Nolan bros and one of the most famous comic books ever). Guess what happens in that... Bruce fakes his death and marries Selina.
And there is no logical reason Alfred would see Selina in the cafe. Nolan makes it a point to have Anne turn her head so that we can see that it is her.
Again, there is NO logical way to assume that he died. None. You just have to watch the movie again and pay attention to the classis misdirections that are there to make us think he died for about 2 minutes.